Data may be communicated over an optical fiber in one or multiple bands. In this manner, for single band optical communication, the allocated spectrum contains content that is produced by the modulation of payload data with a single optical carrier. For a multiple carrier-based communication (or “multi-band” communication), the allocated spectrum is divided into multiple parts of the spectrum called “sub-bands.” Each sub-band is associated with an optical carrier and contains content produced by the modulation of payload data with the optical carrier; and adjacent sub-bands are separated by null points in the allocated spectrum.